It's first time doing comparison photos for lens like this. I decided to do a brick wall test first with Aperture priority mode and tried to maintain an exposure compensation value between +1.0-1.3 EV for both lens to match similar histogram curve.

All photos taken at ISO 125 and RAW DNG files imported into Lightroom 2 and resized without sharpening to 800 pixel width @85% JPEG Quality. Noticed the Sigma @50mm seems a bit wider than Tamron @50mm even though the distance/tripod setup remained the same ?

These are all 100% crops I assume? Otherwise you're only testing for distortion which is moot since you use different focal lengths..

They seem like they have too much distortion to be 100% crops. I wrote an online tool here that helps to compare crops from different lenses. It would be interesting to see 100% crops from the images. I'm surprised the Tamron looks less sharp than the Sigma when they're downsized so much.

I've got the Sigma and it looks like a winner here. Thanks for the walls.

thanks

Originally posted by audiobomber

Would you mind posting a non-brickwall photo without compensation? I'm interested in colour and contrast under the same conditions. If it's not too much trouble.

will do a bit later

Originally posted by bc_the_path

Nice setup, interesting comparison.
I would be happy to read your comments also. Not only on the optical performance, but also on handling... Thanks in advance.

Handling pretty similar both about same weight - the zoom ring on tamron is noticeably tighter to turn than on sigma.

When i got the tamron and did a quick test indoors in very low light conditions and seemed by sigma handled low light better than tamron. When i did brick test i was surprised how much i had to reduce shutter speed compared to sigma lens to get the same exposure. Could of been slight cloudier outdoors when it came to tamron test though.

Originally posted by wallyb

These are all 100% crops I assume? Otherwise you're only testing for distortion which is moot since you use different focal lengths..

Originally posted by walter

They seem like they have too much distortion to be 100% crops. I wrote an online tool here that helps to compare crops from different lenses. It would be interesting to see 100% crops from the images. I'm surprised the Tamron looks less sharp than the Sigma when they're downsized so much.

Nah resized as i couldn't figure out how to do exact dimensional/area sized crops across several photos (still a noob when it comes to Adobe CS3/Lightroom3) lol

Quote:

All photos taken at ISO 125 and RAW DNG files imported into Lightroom 2 and resized without sharpening to 800 pixel width @85% JPEG Quality.

I'll check out your online tool - appreciate it if folks also showed me how i can get crops of multiple images at the exact same dimensions/area etc

Originally posted by kibipod

Seems like Sigma did a better job. Is it because of macro mode? I do not own either of the two. So, no personal experience / bias here.